1. Field of the Invention
The present invention relates to an apparatus and method for controlling power of a radiosonde used for aerological observation and thus, reducing power consumption of the radiosonde.
2. Description of the Related Art
A radiosonde is used for aerological observation and has a function of observing weather conditions including temperature, humidity, pressure, position, and the like, in upper layers of the atmosphere after being suspended from a balloon and elevated into the air, and of transmitting the observed data to a receiver on the ground. The radiosonde includes weather sensors such as a barometer, a thermometer, and a hygrometer for aerological observation, a Global Positioning System (GPS) receiver for position estimation, and a wireless transmitter for transmitting observed data. A general method of elevating the radiosonde is suspending the radiosonde from a balloon injected with a light gas, for example, helium, although an alternative method of dropping a parachute attached with the radiosonde from an airplane also exists.
For example, Korean Patent No. 10-2010-0133106, published on Dec. 12, 2010, titled “Atmosphere Lower Ascent and Descent Observation Experimental Tool” discloses a lower atmosphere ascent and descent observation tool including “a floating balloon, a balloon ascent unit winding or unwinding a connection string connected to the balloon to raise the balloon, a cable tensionmeter for measuring a tension of the connection string connected to the balloon, a radiosonde connected to the connection string between the balloon and the balloon ascent unit to observe atmospheric states, the radiosonde comprising an observation sensor for observing and a global positioning system (GPS) chip for transmitting a position signal of the balloon onto the ground, and a GPS antenna for receiving signals observed by the observation sensor and the position signal of the GPS chip at the ground.”
Forms of radiosondes described in the foregoing may be elevated to an altitude of 35 kilometers (km) above ground level after being elevated from the elevator on the ground, despite horizontal movement based on a wind direction or a wind speed. The radiosonde may transmit weather information observed at regular intervals, for example, at 1 second intervals, while being elevated into an upper atmosphere, to a receiver on the ground. In order to perform the preceding, it is necessary for the radiosonde to satisfy weight requirements, a maximum transmission distance, and an operating time. For example, the radiosonde is required to receive information from a distance of 200 km or more, in consideration of a distance to be traversed, to supply a sufficient amount of power to receive radiosonde data for more than 2 hours, and to have a power weight of 140 grams (g) or less. Therefore, power control technology is necessary to effectively control power consumption of the radiosonde.
Also, radiosondes may be elevated twice per day, simultaneously around the world, to observe upper atmospheric weather conditions, and fall to the ground after the balloon bursts. However, once elevated, a radiosonde may be discarded, rather than being recovered, resulting in environmental pollution. In order to reduce such environmental pollution, minimizing a battery capacity of the radiosonde is necessary.
Further, a radio signal may be propagated in various directions and accordingly, cause a radio interference in adjacent electronic devices and increase a range of signals to be received by a receiver of the radiosonde on the ground. Therefore, a function of controlling a transmission power is necessary to prevent transmission of an extremely strong signal.